A photographic printer loads a negative film on a negative carrier, which is then mounted on a base plate to print the film. This printer is required to have means for placing the negative film in position on the base plate. Specifically, to perform a printing operation efficiently, the center of the negative film must be precisely located on the optical axis of printing, and then the density of the film must be automatically measured with an optical system and image pickup devices. For this purpose, it is desired to mount engaging means between the negative carrier and the base plate to precisely place the carrier in position. The negative film is frequently inserted along the optical axis of printing from the front side. Sometimes, it is necessary to invert and insert it from one lateral side before it is printed.